Could the Fuji T-1, F-86 Sabre, Lockheed F-104 Starfighter and Lockheed T-33A be added to the list for Premium or/and Omitted list? Or the could fit into a slot for Jet Aircraft that is needed and might need buff up to be equal match to other nations? During my research... I couldn't find any more military aircraft made after the war that match with the current game's time frame.

The Fuji T-1 was very lightly armed, the F-104 it's way outside the limits set. As the T-33 is concerned i don't know, technically it could be added although it wasn't designed to fight

20 Aug 1945 U.S. and Japan armistice
02 Sep 1945 U.S. and Japan armistice signed onboard U.S.S. Missouri
18 Sep 1947 U.S. Air Force established as separate service (National Security Act of 1947)
08 Aug 1947 North American XF-86 (XP-86) prototype completed; "first American aircraft to take advantage of flight research data seized from the German aerodynamicists at the end of the war"
01 Oct 1947 North American F-86 Sabre first flight (YF-86D; also known as YF-95A)
22 Mar 1948 Lockheed T-33 first flight; manufactured in Japan by Kawasaki in 1956+
__ Sep 1948 North American F-86A set its first official world speed record of 670 miles per hour (1,080 km/h); still 51 km/h short of Me163B tested by Germans in 1944
22 Dec 1949 North American F-86D prototype first flight
25 Jun 1950 Korean War start

__ ___ 1961 North American F-86D's phased out by USAF; other countries continued to use them

30 Jun 1961 Lockheed-built F-104J makes first flight in Japan (first three built by Lockheed); specialized interceptor version named Eiko (Glory); armed with cannon and four Sidewinders (AIM-9's)__ Mar 1962 Mitsubishi begins production of F-104J's until March 1965;

Given the IL-40P and Gloster Javelin programs active in 1956, it seems to me that the best case could be made for the F-86F built by Mitsubishi under license in 1956 after the Japan Air Self-Defense Force was formed.

However, if this is done for Japan then a similar case could be made for Germany with the F-84F acquired in January 1956 after the Luftwaffe was reformed; yet Germany already has three WW2-era jet lines in game extending to Tier X, some of them from blueprints with zero production. Why then should Japan not get a similar treatment, given there is no shortage of native developments?

North American F-86F Kyokuko (Sunbeam) 「旭光」

Production

Airframe

Engine

Speed

Armament

Bombs

28+180 *

F-86F-40

General Electric J47-GE-27

1118 km/h @ _____ ***

6x12.7mm Browning M3 **

2x454kg

* 28 built by North American; 180 assembled by Mitsubishi

** For reference, the Supermarine Swift in game has a max speed of 1127 km/h at best altitude and the F-86A in game has the same armament

-- You would be giving up extreme speed/maneuverability in order to have a tail gunner or multiple gunners, and would be heavily armored, presumably to deliver a bomb payload in a manner similar to ground attack aircraft currently in game, taking the "sky whale" concept to a whole new level

-- parallel fighters developed as companies competed with each other (Ex. Ki-33)

-- canceled fighter projects

-- modified imports, etc.

Option 7: Some combination of the above

-- such as the "night fighter" variations on any of the above

-- this could contribute directly to the development of the J1N1 dedicated night fighter.

I recognize that most of the aircraft here are going heavily against precedent. My goal here is to get a good look at everything to see how it might fit in. It is really just a sudoku exercise at this point, but there are still some reasonable (or obvious) conclusions to be derived. For instance, a dedicated dive bomber or floatplane progression would probably not arrive before the IJA fighters because there are barriers to implementation. Flying boats are comparable to low-altitude flying fortresses and probably wouldn't even be considered until then if ever. Perhaps another avenue for implementing them would be through alternate battle modes that use AI, but I don't want to speculate about that. Anyway, just to be thorough, here is an interpretation of dive bombers and floatplane progression based on information derived from Francillon and Mikesh.

I believe that dive and torpedo bombers would be more than capable of performing a GA role, so long as they are balanced according to their speed and payload. The Japanese very much show the type's weakness in armament, but if they could perform acceptably if they could fill the role of quick-strike aircraft, able to rush in and claim early superiority before enemy fighters can harass them.

Recon aircraft as well, due to the weak (if any) armament, would need to be balanced to have a speed/altitude advantage just to stay alive, much less be effective in a fight.

As for flying boats... No. They are very large, often with four engines, and (correct me if I'm wrong) don't have hard-mounted forward firepower. As such, they fit in with bombers such as the B-17 and JU-188.

I would agree that floatplanes are the most ideal, as they were often conversions of effective fighter aircraft and carried comparable armaments. I would place torpedo and dive bombers next, followed by the few viable recon planes. and leave the boats strait out.

-- As a replacement for the Kawasaki Army Type 92 Fighter, in June 1933 the Army instructed Kawasaki to begin work on a new fighter. This was to be a radical change in design and was to be a fully cantilever low-wing monoplane which the Army designated Ki-5. The design was initially supervised by Dr. Richard Vogt with chief designer Takeo Doi and the company completed the first prototype in [02/1934]. (In 1933, before the airplane was completed, Vogt returned to Germany as chief desinger, general manager, and part owner of the Hamburger Flugzeugbau.)" (Mikesh, 155)

-- "The Ki-5 had an inverted gull-wing to provide better downward visibility for the pilot and make possible a shorter undercarriage. It was powered by an Ha-9 I water-cooled engine, a development of the Kawasaki-BMW IX, with a three-bladed metal propeller." (Mikesh, 155)

-- "In all, 4 prototypes were built, each having differences in center-section anhedral, outer wing dihedral, fuselage shape, undercarriage configuration, radiator, seat positioning and other refinements. These failed to produce a good airplane with desired visibility for the pilot, or good stability at low speeds. Progressive designs reduced and finally eliminated the inverted-gull wing concept." (Mikesh, 155)

-- "Efforts continued for more than half a year to improve the Ki-5's performance, but in [09/1934] the Army decided that the airplane showed little promise of achieving the desired maneuverability and cancelled the project. In general, test results showed that it had poor lateral stability at low speed and suffered from engine vibration and engine cooling system problems. By now, with the passing of much time, Kawasaki had an alternative, reverting to biplane layout, and the Army then turned its attention to developing this later airplane which became the Ki-10 fighter (Perry)." (Mikesh, 156)

-- for excellent narrative see Wieliczko's coverage of Ki-27 development (Wieliczko, 9).

-- "Chief designer assigned to the project was Shigejiro Ohwada, assisted by Toshio Matsuda. Their design was an advanced low-wing cantilever monoplane with inverted-gull tapered wing. This wing was a metal structure with metal skin on the forward half and fabric-covered rear portion. The fuselage followed the now-established practice of being an all-metal monocoque structure. The undercarriage was non-retractable but the wheels were enclosed by large spats. The Kotobuki 3 engine was enclosed by a close-fitting ring cowling with blisters above the cylinder heads, a relatively new form that was later applied to the Nakajima AT transport. The pilot's cockpit was semi-enclosed by a rearward sliding canopy, said to be the first of its type for a fighter." (Mikesh, 217-218)

-- "Five of these aircraft were built between March 1934 and May 1935 and an Army team led by Capt Yatsuo Yokoyama evaluated the airplanes. During test flights, they were plagued with accidents, none serious, but bad enough to cause damage to the control surfaces which required constant changing. This was mostly aileron damage caused by a wing dropping on landing due to early stalling and it seems that this problem was never completely overcome. A large dorsal fin was added but what effect this had on correcting this control problem is not known." (Mikesh, 218)

-- "Although testing and evaluation continued for some time, the Army did not have a policy covering the use of two-seat fighters, and as a consequence the airplane was never accepted as standard equipment. It was reported, however, that the general performance of the Ki-8 was almost equivalent to that of the light-weight single-seat Type 91 Fighter." (Mikesh, 218)

-- "In a new fighter competition organized by the Army in 1934, in which Mitsubishi was not initially involved, Nakajima submitted a low-wing monoplane with non-retractable undercarriage, which looked similar to the Boeing P-26, and it became the Ki-11. Kawasaki's entry was a sesquiplane fighter, to be known as the Ki-10. The Ki-11 was slightly superior to the Ki-10 in speed, yet the Ki-10 was more maneuverable. The latter airplane, however, was accepted by the Army as the Type 95 Fighter, but without much enthusiasm." (Mikesh, 186-187)

-- "At this time Mitsubishi's Navy 9-Shi Fighter was showing outstanding performance and not only captured the respect of the Navy, but of the Army as well. With the Navy's consent, the Army ordered an example of the 9-Shi Fighter (which developed into the A5M1, Allied code-name Claude) for evaluation. It was to have Army equipment and systems to replace those of the Navy. This became the Ki-18. Changes from the Navy model were in the direction of the throttle movement (in the Army forward was idle) and substituting Army standard machine-guns. The reverse movement of the throttle probably resulted from French influence." (Mikesh, 187)

-- "The new airplane was completed in August 1935 and evaluated until the following spring at the Air Technical Research Institute at Tachikawa and later at the Akeno Army Flying School. In the early part of 1936 the Kotobuki 5 engine was changed to the Kotobuki 3 at the suggestion of Capt Oujiro Matsumura, an instructor at Akeno. The direct-drive Kotobuki 3 seemed to be an Army preference. During these tests, flown primarily by Capt Akita, a maximum speed of 240 kt [445 km/h] at 3050m was recorded, and the airplane was able to climb to 5000m in 6:26 -- an exceptional rate. These remarkable tests continued until the Ki-18 was badly damaged in a landing accident." (Mikesh, 187)

-- "Opinions by those who flew the airplane were that stability and control could be improved but no changes were made. However, while the Ki-18 was being evaluated at the Akeno Flying School, it gained excellent marks in every respect and it was requested that further models be produced. These Akeno recommendations were countered by the Air Technical Research Institute expressing dissatisfaction with the engine which it termed unreliable. Supporting this claim, the senior organization, Army Air Headquarters, concluded that the Ki-18 had insufficient performance for acceptance as an Army fighter. Therefore, a new competition would be staged, inviting three aircraft companies to participate. Thus, the Ki-18 ended with only the one aircraft, to the astonishment of Mitsubishi, because of the dissatisfaction expressed by the Air Headquarters, while this same airplane was considered a revolutionary fighter for the Japanese Navy. One might speculate that the never-ending rivalry and jealousy between the Army and Navy had much to do with this decision." (Mikesh, 187)

-- "After the failure of the Ki-11 and the non-acceptance of the Ki-18, the Army informed three of the major aircraft manufacturers in [12/1935] that a competition would be held for a new fighter the following April. This date was based upon the expected availability of the new Army Ha-1 Ko engine. Features asked for in the competition closely followed those of the rejected Ki-18 (A5M1)." (Mikesh, 187)

-- "In response, Mitsubishi engineers felt that the company was too involved with the two 9-Shi aircraft, the A5M fighter and the G3M bomber, both of which had recently been accepted by the Navy. There was no advantage in diluting manpower resources with separate projects for both the Army and the Navy. In addition, the rejection by the Army of the Ki-18 in light of its outstanding capability was considered to be a second rejection on principles rather than quality." (Mikesh, 187-188)

-- "An internal debate between Mitsubishi's marketing division and its engineers brought about a compromise that the Army's purchase order would be honored provided it did not cause a noticeable drain upon engineering resources unless such design work was absolutely necessary." (Mikesh, 188)

-- "The new fighter was designated Ki-33. Chief designer was Jiro Horikoshi, who had designed the 9-Shi Fighter. By [08/1936], the first prototype was completed, far earlier than the other companies' prototypes. This was understandable because Mitsubishi had current fighter designs and fabrication experience with existing models. When the second prototype was completed, both aircraft were delivered to the Army after inter-company flight tests at Kagamigahara." (Mikesh, 188)

-- "In appearance, the Ki-33 closely resembled the Navy A5M1 Fighter, as did the Ki-18 which had been rejected. What made this airplane significant, aside from the Ha-1 engine replacing the Kotobuki 5 engine, was the wash-out of the wing that Horikoshi introduced into the design of the second prototype which had a conventional wing. This wash-out reduced wingtip stall at high angles of attack, which is so essential for improved maneuverability when dog-fighting." (Mikesh, 188)

-- "Mitsubishi's competitors were much later with their test aircraft. By the time they produced their second prototypes, they too had the wash-out feature incorporated into the wingtips. The results of the evaluation concluded that the Ki-33 was superior to the Nakajima Ki-27 both in speed and control. However, the prolonged evaluation of the two designs resulted in modifications made by Nakajima to the Ki-27, some of which included newer wing designs with different wing area and wash-out. Mitsubishi made few if any changes to its Ki-33, recognizing a pattern, either real or imagined, of the rejection cycle that had occurred with its Ki-18." (Mikesh, 188)

-- "As a consequence, the Nakajima Ki-27 was determined to be the superior fighter and was accepted by the Army as the Type 97 Fighter. Kawasaki's Ki-28 with its water-cooled Ha-9 II Ko recorded the maximum speed of 261 kt [483 km/h] during the winter season (speed would have decreased by 5.5 kt during the heat of summer). The fighter failed in the competition because Kawasaki ignored the importance placed by the Army on maneuverability for dog-fighting rather than pure speed." (Mikesh, 188)

-- "The Ki-33 differed from the Ki-18 mainly in that it had a new, air-cooled 9-cylinder Nakajima Ha-1a radial (an elaborated Kotobuki) of 620/745hp, a different engine cowling, slightly redesigned fin and rear fuselage, and a half-enclosed cockpit with a backwards sliding canopy consisting of one top and two side glass panels ... second prototype, Ki-33.02, was completed in late 1936." (Wieliczko, 12)

-- designed by Tsuchii Takeo after 08/1942, possibly inspired by H.M. Poyer's Bell P-39 Airacobra which saw limited action in the Battle of Guadalcanal. (Francillon); By moving the engine further back in the fuselage, heavy armament could then be placed in the nose with the benefit of improved accuracy (image 1 / image 2); radiator almost directly underneath pilot seat; fuel tanks in the wings behind each wheel well; air scoop for turbo- or supercharger on left side of the fuselage, just above the trailing edge of the wing (Francillon, Dyer); development of the prototype was halted after 06/1943 in favor of the Ki-61, which was already in production (Francillon)

-- Payen adapted his Pa.112 concept to be a carrier-borned light bomber, to be called Pa.400

-- September 23 1938, French government authorizes sharing technical information

-- project abandoned either due to Payen not sharing the information on the brink of war, or IJN losing interest

-- Dyer explains several technical limitations of the design that may explain possible loss of interest by IJN

-- no prototypes produced

Source: Edwin Dyer

A7M3:

-- A7M3-J concept was to be powered by turbosupercharged version of the MK9A; max speed 649 km/h at 10,000m expected

-- design complete November 1944

-- mock-up inspected February 1945

-- prototype planned for October 1945, interrupted by surrender

-- a further development of the A7M3-J (using a different engine, and carrier-based) was left on the drawing board at surrender

-- A7M3 Model 23 was to be designed around MK9C with a mechanically-driven three-speed supercharger; 642 km/h max speed expected at 8700m

-- Model 23 favored over the J because it could use the A7M2 airframe without major redesign

-- armament to be 6x20mm Type 99 Model 2's in the wings

-- scheduled to be completed by December 1945, interrupted by surrender

-- no prototypes produced

Source: Rene Francillon

I will look closer at the other aircraft in your list. If you can recommend sources other than Francillon or Dyer I would be glad to check them out.

When I began this project I had to set several rules for myself in order to have a clear direction. One of the rules was that I was going to give preference to high-production aircraft (those that were actually in the war); yet I have discovered that the tech trees of other countries do not necessarily adhere to that rule. The Russian attack line for example has several IL's that never had more than 10 produced, yet they are there presumably to complete the line and offer an alternate path of progression. Another example is the Bf 109 Z (only one built, but never flown). I could certainly use the that precedent (or the J7W3) to devise any tree I want in the name of fun, but then it becomes deeply subjective and not very useful for making predictions.

I don't know how to account for the "fun factor" but I imagine it would involve identifying different themes and trying to work them into the tree, such as:

-- a fighter line that focuses on speed and rate of climb rather than maneuverability

-- a discernible ground attack line

-- a discernible heavy-fighter line or "night fighter" concept if maps are made to be dark ***

-- a dive bomber line if it becomes relevant

Anyway, I'll leave the "fun factor" to developers because it is their business and I think they've done a great job so far. I'm kind of hooked if you haven't noticed. If nothing else comes of this tech tree adventure then it has certainly been fun just learning about all of the different aircraft.

Seeing that WoT and WoWP are run by the same folks and share a common general plan for the games ( allowing vehicles in game that did not get off paper or out of prototype ) to dismiss an aircraft because it did not fit into the realm of deployed, functioning planes is incorrect as far as this game goes. The JPE-100 in WoT is a prime example of that.

The current tree is fine for making predictions, but there is room for improvement. I am working on an improved tree to resolve these things:

1. Organization by manufacturer (Mitsubishi, Nakajima, Kawasaki), not Army/Navy by production values.

-- Army/Navy distinction made sense in the beginning to reduce chaos, but if implemented as such it would be the only tree to be organized that way

In a sense, the American fighter lines are organized by Army/Navy, as in the Grumman/Vought line are carrier-based planes, whereas the Curtiss/North American line are land-based planes (but for gameplay purposes the FJ-1 was designated normal fighter even in the days when CBF designation existed).

WoWP makes a great jousting game...especially with the 262 and people busy in furballs...
I am deaf, silent, and fly with unrealistic controls. Do not count on me to carry - my back's already broken from overweight.

Yes; that was the main reason for organizing along Army/Navy lines to begin with, along with Francillon's organization, but I am finding that if I follow the French model (that has no choice but to ignore the distinction) then organization by manufacturer (Demon93's method) with minor developments to fill the gaps, it starts to look really good. I think you'll see what I mean ... here is a rough overview:

FIGHTERS

"Mitsubishi"

"Nakajima"

"Kawasaki"

I

Type 91 (05/1928)

II

A4N (1934)

Ki-11 (04/1935)

Ki-10 (03/1935)

III

A5M (02/1935)

Ki-27 (10/1936)

Ki-28 (~10/1936)

IV

A6M1 (04/1939)

Ki-43 (01/1939)

Yokosuka D4Y1 (12/1940)

V

A6M2 (12/1939) ------------>

Ki-43-III (05/1944+) or Ki-44-I

Ki-60 / Ki-61-I (03/1941) / (12/1941)

VI

A6M5 (1943+)

J2M (03/1942)

Ki-44-I/II (08/1940) (08/1942)

Ki-61-II / Ki-100 (12/1941) / (02/1945)

VII

A7M (05/1944)

N1K1/2-J (05/1942) (12/1943)

Ki-84 (04/1943)

Ki-119 (~09/1945)

VIII

Kyushu J7W1 (08/1945) <--

J4M (1943+)

Ki-87 (04/1945) -------------->

Kitsuka (08/1945)

Ki-64 (12/1943)

IX

Kyushu J7W2

J8M (1945)

Ki-201 (1945) <----------------

Yokosuka R2Y2 (1945)

X

Kyushu J7W3

Rikugun Ki-202 (1945)

Variable 2

Organized this way it starts to look more like the playable trees of other countries, rather than "fanning out" at VII/VIII. It also comes close to maintaining consistent themes for each line:

Kawasaki/Yokosuka -- German water-cooled engines produced by Kawasaki and Aichi until Ki-61-II; fighter bomber trend continued by Yokosuka; primary designer Takeo Doi of Kawasaki (influenced by Richard Vogt).

Heavy fighters are their own challenge, but by eliminating Army/Navy distinction it is possible to have them together off to the right of Kawasaki (similar in manner to the German tree), and allows a distinction to be made between those that favor large calibers (Heavy I), and those that favor a lighter/faster approach (Heavy II), in order to have everything included:

It is true that IJN and IJA functioned independently (specifications, resources, designations), but it is equally true that the major companies competed with each other for contracts across Army/Navy lines, used each others' engines along the way, and even collaborated across the line towards the end, so proceeding in this manner is not unreasonable.

-- accommodates a wider spectrum of aircraft without making arbitrary exclusions; establishes clear room for growth

CON

-- tier placement by engine horsepower dampens the advantage held by J2M and N1K1-J development; chronology would otherwise put them 1 tier ahead relative to the Nakajima line

-- There are several minor disagreements in chronology due to sequential, protracted, or continued development, as indicated by the first flight or expected completion date (parenthesis), but I suspect that this might be resolved by looking closer at when the specifications or contracts were issued (truer/wider chronologies with acceptable overlap)

-- smaller pool of potential premiums

Sources:

-- Kawasaki Ki-88 in game

-- Daimler-Benz engine details from German tech tree in game (produced and modified further by Kawasaki and Aichi)

-- engine details on page 5 of this thread (sources noted)

-- Japanese Aircraft of the Pacific War, by Rene Francillon (1970)

Anyway, that's the proof of concept for a full-saturation model and might be closer to what eventually takes shape.

Sorry, I just had to point out. The Japanese characters for the F-86-J's nickname, Kyokkou are mistaken. the correct characters are「旭光」.

In addition, the T-1 training craft was designed not only to hold one 12.7mm heavy machine gun for shooting practice, and had the capacity to mount either Sidewinder AAMs, bombs, or gunpods on the wings. though as WG seems adamant on not implementing missiles, the armament on the T-1 would be limited to the guns and 2 750kg bombs.

Also, why does everyone reffer to the Kikka as "Kitsuka"? The 'tsu' in「きっか」is pronounced as a sharp sound after the 'Ki', and not as its own word.

[work in progress ... differences between historical/implemented Japanese jet engines make this more complicated, but it should still be possible to establish parameters ... this will be resolved very soon]

The general trend for speed (historical values/estimates) is consistent with tier progression.

Hey everyone! We apologize for the delay in getting these answers to you; we've taken the top questions from April and May and combined them into one thread:

Question: Are there any plans to add the Beta planes (P-39, P-51 JP, Me 609, J4M1, Me 109 TL, etc.) and nose art that were removed prior to release? Will we eventually see them in upcoming patches?

Answer: Some of them have already been added into the game (like the P-39 in 1.4.0, a USSR LVL6 Premium); some of them will be added in the near future (for example, in 1.6.0); and some of them a little bit later. The same thing with the nose art as well.

...

Q: What are the plans for future GA lines? Or could we get a teaser for the German GAs?

A: There are planes for future GA lines, but we are not ready to tease the details just yet. Sorry!

Q: 75mm guns were mounted or planned for on the B-25G, A-26, Ki-93 and Hs-129, among others. Are there caliber limits placed in WoWP - if so, how large can a cannon be - if not, can these planes be expected to be seen?

A: We have no technical limits for caliber of guns! In reality, 75mm guns were powerful and specialized anti-tank guns. Aircraft armed with such a caliber had very little maneuverability and were not suitable for air combat. The rate of fire of these primary weapons were only what was necessary to take out tanks. We have not introduced these guns as planes equipped with them would be almost defenseless against fighters, and with current ground targets it is better to fight with rapid-fire guns. But with progressive ground-target types, such calibers might possibly be needed--but probably not soon.

^ That essentially means Nakajima J5N1 and/or Aichi S1A for Tier VII, and if Ki-93 is to appear anytime soon it will be the 57mm version.

Thank you to Wargaming for making such a fun and addictive game; my local and state library system for making historical research possible; and thank you to the experts in this thread that provided the kind of targeted advice and enthusiasm that kept me going in the right direction.

This post is reserved for a detailed examination of the "B" series of IJN aircraft.

This is necessary in part to identify the exact origin of the Nakajima Kikka.

Kusho B3Y1 (1933) -- Navy Type 92 Carrier Attack Bomber

Production

Airframe

Engine

Speed

Armament

Bombs

1 by Kusho ... Kusho Type 13 Kai (1932)

75 by Aichi (1933-1936)

23 by Watanabe (1933-1936)

~30 by Hiro Arsenal

B3Y1

Hiro Type 91 600-750hp

219 km/h

1x7.7mm fixed forward

1x7.7mm flexible rear

1x800kg torpedo or

1x500kg bomb or

2x250kg or

6x30kg

Data: Mikesh.

Notes:

-- "Under the design guidance of Tamefumi Suzuki ... modifications made by Tokuichiro Gomei of Aichi ... officially accepted by the Navy [08/1933 due to Gomei's modification]. Production was placed with Aichi, followed by Watanabe and the Hiro Arsenal after the prototype was built at the Yokosuka Arsenal ... early stages of the Sino-Japanese conflict ... noted for their success in level bombing against small targets ... gradually replaced [by D1A1, D1A2, B4Y1]." (Mikesh, 280-281)

-- "The Arsenal's project was the work of Sanae Kawasaki, who endeavoured to design an aircraft capable of receiving various types of powerpants and making use of existing components. To realize his goal ... matched a new fuselage and tail section to the wings of the Kawanishi E7K1 which had been found highly efficient. The first B4Y1 prototype of this hybrid, powered by a Hiro Type 91 600hp liquid-cooled engine, was completed and flown in late 1935." (Francillon, 449)

-- "...regarded as a stopgap pending availability of a more modern aircraft possessing performance more compatible with that of the Navy Type 96 Carrier Fighter [A5M]." (Francillon, 412)

-- "For Nakajima the design of the new aircraft was shared by Takao Yoshia and Yasuo Fukuda. Two prototypes were completed in 1936, one powered by a Kotobuki 3 engine, and the other by the Hikari 1." (Mikesh, 236)

-- "Of more conventional construction than the Nakajima B5N1, its competitor ... initially favored by the Navy ... put into production as the Navy Type 97 Carrier Attack Bomber Model 2; but production was terminated after the delivery of 125 machines because in service the Nakajima aircraft proved highly successful. During the Pacific War, the B5M1's were operated from land bases in Southeast Asia for a brief period before being relegated to ancillary duties." (Francillon, 491)

-- "...were used only for anti-submarine patrols from Southern China and Hainan." (Hawkins, 6)

-- "Under the leadership of Katsuji Nakamura, the Nakajima design team adopted for their Type K a clean low-wing configuration fitted with a hydraulically-operated undercarriage. The large wing could be folded upwards, and the hinge points were arranged so that the wingtips overlapped each other when folded above the cockpit. When compared with the massive wing, the fuselage appeared small as overall length was kept to 10.3m to enable the aircraft to be accommodated on the standard deck elevators of the Navy carriers. Other innovations incorporated ... included Fowler flaps and variable-pitch propeller. Bearing the official designation B5N1, the prototype ... was completed [12/1936] and made its first flight [01/1937]." (Francillon, 412-413)

-- "...starting with the second prototype, the hydraulic wing-folding mechanism was replaced my a manual-folding system and the Fowler flaps were changed for more conventional units. Further changes ... included replacement of the Hikari 2 by a Hikari 3 driving a constant-speed propeller and the installation of integral wing tanks with increased capacity. In this form the aircraft won the competitive trials over the Mitsubishi B5M1 and went into production [11/1937 at Koizumi] as the Navy Type 97 Carrier Attack Bomber Model 1. After an initial crew training period in Japan ... later redesignated Navy Type 97 Carrier Attack Bomber Model 11, went into service aboard Japanese carriers. Meanwhile land-based units took the aircraft into combat operations on the Chinese mainland where, armed with bombs, it served as a tactical bomber in support of ground operations. Operating under the cover of escorting [A5M's], the B5N1 was quite successful in spite of its lack of protection for crew and fuel tank and its modest defensive armament." (Francillon, 416)

-- "In level bombing sorties ... the observer was responsible for aiming the bombs. Seated between the pilot and radio operator, he could see the target by opening a pair of small folding doors in the floor of the fuselage." (Francillon, 413)

-- "It exhibited several advanced features for its time, and its design was influenced in no small part by the Northrop 5A, an example of which had arrived in Japan in 1935 ... [B5N1 prototype] was a clean-looking 2/3-seat monoplane with mechanically folding wings, Fowler-type landing flaps and a fully retractable main undercarriage. Its 770 hp Hikari 3 radial engine was installed beneath a neat NACA cowling ... saw combat service in the Sino-Japanese conflict ... Production of the B5N1 was simplified by adopting manual instead of mechanical wing-folding, and by substituting slotted flaps for the Fowler type. Late production aircraft (designated Model 12) were fitted with 985hp Sakae 11 engines. (Munson, 104)

-- "The operational debut ... occurred in late 1938 when they were used as land based aircraft for close support of the Army in the Hankow region of China." (Hawkins, 7)

-- "The only other obvious airframe change was the fitting of an aerial post above the rear cockpit." (Hawkins, 7)

-- "At the time of the Japanese attack on Pearl Harbor [12/1941], the B5N's had completely replaced the earlier B5N1's and B4Y1's in first-line units of the Navy ... replaced [1944] by the Navy Carrier Attack Bomber Tenzan [B6N]." (Francillon, 414)

-- "A prototype appeared in [12/1939] of the B5N2 Model 23, a torpedo bomber version powered by a 1115hp Sakae 21 engine. This was armed with two forward-firing guns and one or two guns in the rear cockpit; and it could carry an 18in torpedo or bombs under the fuselage ... entered JNAF service in 1940, and both variants were concerned in the attack on Pearl Harbor [12/1941]. Subsequently they were responsible for the destruction of several other major U.S. carriers during the early part of the war." (Munson, 104)

-- after relegation to second-line units, used for reconnaissance and anti-submarine roles ... "some B5N2's were fitted with Air-to-Surface Vessel Radar ... while other received Jikitanchiki magnetic airborne submarine detection devices." (Francillon, 414)

-- "The Hawaiian Operation, as the attack on Pearl Harbor is known to the Japanese, go underway on [11/22/1941] ... The 100 B5N2's, carrying torpedoes and armor piercing bombs, and the 40 D3A1 dive bombers were escorted by A6M2's ..." (Francillon)

-- "...encountered operationally as late as [06/1944], when a number were engaged in the Mariana Islands campaign ... More than 2,200 ... were completed, some of them by Aichi ..." (Munson, 104)

Data: Francillon. Of the total 1266 production aircraft built, 296 built at Koizumi, 970 built at Handa.

Notes:

-- "...designed by Kenichi Matsumura to a 14-Shi specification issued in 1939 by the Imperial Naval Staff ... The Navy insisted on powering the aircraft with a [Kasei], but Matsumara elected to use the new [Nakajima Mamoru 11 1870hp] as it had a lower fuel consumption and a better growth potential. With this powerplant installed the first two prototypes were readied for flight trials in the spring of 1941." (Francillon, 429)

-- "Unfortunately, early flight test reports indicated that the design suffered from serious engineering defects. The most urgent modification affected the vertical tail surfaces which had to be moved 2 deg 10 min to the left to correct directional stability problems from the powerful torque of the four-blade propeller ... [improved flying characteristics] ... but teething troubles, particularly with the Mamoru engine, slowed its development. By [end of 1942] the Navy Experimental 14-Shi Carrier Attack Bomber was considered ready for carrier acceptance trials ... [several landing mishaps] ... In early 1943, with the hook mounting strengthened, the B6N1, although requiring the use of [RATO] for take-off at maximum gross weight, completed its carrier acceptance trials successfully." (Francillon, 430-431)

-- "After more than two years of testing [finally accepted for production] as the Navy Carrier Attack Bomber Tenzan (Heavenly Mountain) Model 11 ... [several modifications for production aircraft inluding] 1) replacement of single exhaust stack, which produced excessive glare at night, by a series of smaller exhaust units; 2) torpedo rack under the starboard fuselage side angled down 2 degrees, and provision for torpedo stabilizing tail plates to eliminate a tendency for the torpedo to bounce during low-altitude release; 3) strengthening of main landing gear attachment and of the tailplane; 4) addition of a flexible 7.7mm machine-gun firing through a ventral tunnel. Attempts were also made to replace the unprotected semi-integral fuel tanks with protected bag-type tanks, but this modification resulted in a 30% reduction in tank capacity [therefore rejected]. In service the Tenzan performed satisfactorily, but its high landing speed and wing loading restricted its use to the larger carriers." (Francillon, 431)

-- "... carried dorsal and ventral machine-guns, the latter gun being extended into the airstream after the torpedo had been released, to discourage anti-aircraft fire from the ship just attacked." (Munson, 109)

-- fully-retractable tail-wheel [B6N1]. (Francillon, 432)

-- "First combat appearance of the Tenzan was [12/1943], when a group of B6N1's attacked a U.S. task force off the Marshall Islands, but most of the 1,268 Tenzans built at Nakajima's Handa and Koizumi factories were B6N2's [which made their] first operational appearance in the Marianas campaign [06/1944], and was encountered again in engagements in the Caroline and Solomon Islands groups and at Iwo Jima." (Munson, 109)

B6N2

-- Navy Carrier Attack Bomber Model 12 ... also undergone a number of minor internal changes and were fitted with a non-retractable tailwheel ... late production B6N2a Model 12a ... armed with [13mm Type 2 rear]. Two B6N2's (No. 751 and 752) were modified to [accept Kasei 25c 1850hp] and featuring strengthened undercarriage with larger wheels intended for operation from land bases with semi-prepared runways, as by then the Navy was practically without any aircraft carriers. The production of the B6N3 had not yet started when the war ended." (Francillon, 432)

-- "... [B6N2 Model 12], powered by the more reliable Mitsubishi Kasei 25, which offered a lighter installed weight and more straightforward maintenance for only a slight reduction in output ... named Tenzan by the Japanese, after a Chinese mountain ..." (Munson, 109)

-- "In the B6N2 an additional forward-firing gun was provided in one wing. To avoid fouling the bombs or torpedo, the oil cooler was offset to port on the lower portion of the engine cowling." (Munson, 109)

Data: Francillon * same engine used in N1K1-J**same engine used in N1K4-J***same engine used in Mitsubishi A7M2 B7A2 climb: 6:55 to 4000m; ceiling 11250m

Notes:

-- "...to supplement and eventually replace both the Nakajima B6N torpedo-bomber and the Yokosuka D4Y dive-bomber." (Francillon, 288)

-- "...designed by Norio Ozaki, Morishige Mori and Yasushiro Ozawa to meet a specification which called for a high-performance carrier-borne torpedo-bomber, or 'attack-bomber', with the maneuverability of a fighter. A mid-wing configuration was adopted to provide clearance for a ventral bomb-bay and a large air-screw [4-blade]. The wings had therefore to be of inverted gull-wing shape, since otherwise the legs of the retractable undercarriage would have been too long. The almost untried [18-cylinder Homare], on which the naval authorities insisted, proved troublesome, but eventually its imperfections were overcome ... Too large to be accommodated in fleet carriers of the Akagi or the Shokaku class, they were intended for a new generation of carriers capable of handling aircraft whose length exceeded the limit of 11m previously imposed ... those ready for service by the end of the war were allotted to land-based units." (Collier, 57)

-- "The wings were also fitted with drooping ailerons, which could be deflected 10° to serve as auxiliary flaps, and dive brakes were mounted on the undersurface ahead of the flaps between the fuselage and ailerons. For carrier stowage the wings folded hydraulically upwards outboard of the flaps ...first prototype completed [05/1942]. As the aircraft was the first to be powered by the still experimental [Homare 11 1800hp], the flight trial program was constantly interrupted by engine teething troubles, but when the Homare 11 performed smoothly the B7A1 demonstrated sparkling performance and excellent handling characteristics ... In [04/1944] an improved engine version, [Homare 12 1825hp], became available and ... finally placed in production as the Navy Carrier Attack Bomber Ryusei." (Francillon, 289-290)

-- "Production ... finally brought to a standstill when the Funakata plant was destroyed [05/1945 earthquake] ... however, this no longer affected the outcome of the war because the Japanese Navy had lost their carrier fleet and the small number of B7A2's built saw limited service from land bases with the Yokosuka and 752nd Kokutais." (Francillon, 290)

-- Francillon confirms that a B7A2 was experimentally fitted with [Homare 23 2000hp], but also claims that the projected B7A3 Ryusei Kai was to use [Mitsubishi MK9A 2200hp]. He also claims that a smaller/faster successor to the B7A called Mokusei (Jupiter) was in the early design phase at war end [no other details given] (Francillon, 290-291).

-- "Originally, Fukuda contemplated the use of two 1,000 hp radial engines mounted in tandem, but a single, small-diameter Homare engine, which promised to develop around 2,000 hp, was chosen instead. To shorten ... the development period, no less than 23 prototypes were ordered ... many of these completed by the end of 1943. Several of the prototypes were assigned to active units as part of the test program, and it was they that made the aircraft's operational debut ... first encountered [06/1944], when a number of these ... made a reconnaissance of the U.S. task force assembling for the attack on the Marianas Islands." (Munson, 112)

C6N1

-- D4Y2-C reconnaissance --> Nakajima C6N1 (FF 05/1943)

-- "The first major operation in which the C6N1 took part was the battle of the Marianas. From then on, taking advantage of their range of over 3,000 miles ... effectively shadowed the U.S. Fleet, for their speed, almost equal to that of the Grumman F6F-5 Hellcat, rendered them almost immune from interception." (Francillon, 436)

-- The last confirmed aerial casualty of the war ... C6N1 shot down at 0540 on 08/15/1945 by LCDR Reidy. (Francillon, 439)

C6N1-B Model 21

-- "...projected carrier-borne attack bomber retaining the Homare 21 engine of the reconnaissance version but featuring provision for a torpedo mounted externally, offset to starboard, under the fuselage. Forward-firing armament was to be installed, but the loss of most Japanese carriers eliminated the need for such an aircraft ..." (Francillon, 436)

-- "The C6N1-B was a 3-seat torpedo bomber conversion." (Munson, 113)

C6N1-S

-- "...the sudden need for night fighters to defend the Japanese homeland against B-29 attacks led to the modification of the Saiun to meet this role ... reduced crew of two, and a pair of 20mm Type 99 cannon mounted obliquely in the fuselage ... original performance was retained. As the effectiveness of the Saiun was impaired by the lack of airborne radar equipment, only a few Saiuns were converted to C6N1-S ... but they were the fastest night fighters available for the defense of the Japanese homeland." (Francillon, 436-437)

C6N2 and other plans

-- "With a view to improving the altitude performance ... Nakajima experimentally fitted a turbosupercharged NK9K-L Homare 24 in a prototype designated C6N2. Flight testing ... was still underway when the war ended. Plans ... to manufacture, as the C6N3 Saiun KAI 1, a night fighter version ... powered by the turbosupercharged Homare 24 ... not realized. Three other advanced versions ... C6N4 Saiun KAI 2 [Mitsubishi MK9A] ... C6N5 Saiun KAI 3 ... C6N6 Saiun KAI 4 [all wood] ... were still on the drawing board when the war ended." (Francillon, 437)

-- "The final development, designated C6N3 Saiun-Kai, was to have been powered by a Hitachi 92 engine, but this had only reached the project stage when the war ended." (Munson, 113)

-- [sidenote: the "Hitachi 92 engine" referred to by Munson may be the same as the Hitachi Ha-51 under development at war end mentioned in U.S. Bombing Survey Report]